The field of the disclosure relates generally to gas turbine engines and, more particularly, to a method and system and for damping resonance from, and limiting deflection of a gearbox in a gas turbine engine.
Gas turbine engines typically include integrated drive power gearboxes that transfer energy from one shaft to another shaft. Planetary integrated drive power gearboxes are typically used in aircraft engines because of their compact design. The shafts are typically mounted on soft bearing supports that allow compliance and flexibility to limit shaft bending during high external stresses external misalignment. Planetary gearboxes include a number of rotating gears, which can wear over time from misalignment caused by external stress. To mitigate misalignment, the gearbox is flexibly mounted to the engine casing by a soft mount structure to isolate the gearbox from externally applied misalignments. Deflection limiters are typically utilized to constrain the amount of movement of the gearbox that is allowed by the flexible mounting structure. The rotating gears of the planetary gearbox can also create vibration that can be transmitted to the engine casing, particularly when moving across rotation speeds that create resonances within the engine structure.
Dampers have been employed to attenuate the effect of vibration at resonance crossings, whereas a deflection limiter is a “hard stop,” which prevents significant movement of the gearbox, or individual gears therein, past a particular point. Gearbox movement can be in the axial direction of the shaft, in the radial direction perpendicular to the shaft, and/or in the circumferential direction, that is, rotational movement of the gearbox about the shaft. Deflection limiters have sometimes been employed together with a damper, but such limiters have been restricted to be able to only prevent movement in one of the axial and radial direction.